1. Field of the Invention
The present invention relates to a drive simulation apparatus which is constructed such that the swinging movement of a motion base is controlled, and a simulation image, which is formed on a screen in front of a cockpit, is controlled in accordance with operation of a driver in the cockpit which is installed on the motion base.
2. Description of the Related Art
A drive simulation apparatus has been hitherto known as an apparatus to be utilized, for example, for skill training for drivers and for research and development of automobiles. Such a drive simulation apparatus basically comprises a cockpit for seating a driver to perform various operations, a screen for displaying a scene including a driving road and objective vehicles in front of the driver by using computer graphics, a motion base for supporting the cockpit and swinging the cockpit in accordance with the operation of the driver, and a control unit for controlling the above (see Japanese Laid-Open Patent Publication No. 8-248872).
In such a drive simulation apparatus, it is demanded that the driver is able to physically feel an operation feeling and driving situations which are more approximate to those obtained by a real vehicle.
In order to realize such a demand, for example, it is necessary that the information on the operation of the driver is transmitted In detail to the external control unit, and the motion base is operated, on the basis of the transmitted information, In a state similar to a real vehicle as approximately as possible. It is also necessary that an appropriate image is displayed, on the basis of the operation information of the driver, on the screen which is disposed in front of the driver. The drive simulation apparatus does not run on an actual road surface. Therefore, for example, it is necessary that a steering wheel is controlled by the external control unit in accordance with the operation information in order to apply a virtual reaction force to the steering wheel.
In such a drive simulation apparatus, a large number of operation equipments to be operated by the driver are arranged in the cockpit, including, for example, the steering wheel, a brake pedal, an accelerator pedal, a shift lever, and a head light switch. A large number of wirings are required in order that signals from the operation equipments are transmitted to the external control unit, or control signals are transmitted from the control unit to an electric power steering unit.
However, the cockpit, which is connected to the external control unit via the large number of wirings, makes swinging movement considerably strongly during the operation. Therefore, it is feared that the presence of the large number of wirings causes any trouble such as disconnection. In order to prevent any accident such as disconnection beforehand, for example, it is necessary that the wiring is made thick, or the wiring itself is supported by a swingable mechanism. However, if such a countermeasure is adopted, the cost of the entire apparatus is consequently increased. On the other hand, if the number of wirings is decreased in order to avoid disconnection or the like, the amount of controllable information is decreased. As a result, it is difficult to control the cockpit in a state approximate to a real vehicle. Therefore, it is impossible to perform any appropriate simulation.
The motion base comprises a plurality of actuators composed of, for example, hydraulic cylinders or electric cylinders in order to allow the cockpit to make pitching, rolling, and yawing actions. However, in order to obtain an action range of the cockpit approximate to that of a real vehicle, it is necessary to sufficiently ensure the stroke of each of the actuators. However, if it is intended to ensure a sufficient stroke, then the motion base inevitably has a large size, and the entire apparatus has a large size as well.
In order to create the road surface reaction force and obtain the same steering feeling as that of a real vehicle by using the steering unit of the drive simulation apparatus which involves neither road surface nor tire, it is conceived that an actuator such as an electric motor is attached to a steering shaft to give a steering reaction force in a simulated manner (see Japanese Laid-Open Patent Publication No. 7-234628). However, in order to obtain the same steering reaction force as that actually obtained, it is necessary to perform complicated control considering, for example, the friction of the steering system. Therefore, the cost becomes expensive as well.
On the other hand, when the same components as those used in a real vehicle are used for the steering wheel, the brake pedal, the power window, the air conditioner, other operation equipments, and meters which are arranged in the cockpit, then an obtained apparatus is advantageous in cost, and such an apparatus makes it possible to physically feel driving situations which are more approximate to those obtained by the real vehicle.
In the case of a real vehicle, an electric equipment system concerning the operation equipments and the meters is usually driven by DC 12 V which is supplied by being generated by an engine. However, in the case of a drive simulation apparatus, no engine is carried for the purpose of power generation. The drive simulation apparatus is used in a state of being fixed in a room. Therefore, the necessary electric power is acquired from a commercial AC power source. The alternating current, which is supplied from the commercial AC power source, is converted by an AC-DC converter into a direct current which is supplied to the electric equipment system concerning the respective operation equipments. However, such an electric equipment system requires large electric current consumption in some cases. For example, the electric power steering unit, which generates the reaction force for the steering operation by driving an electric power steering-driving motor, is connected to the steering wheel. Further, an ABS unit, which performs ABS control for the brake by driving an antilock braking system (ABS)-driving motor, is connected to the brake pedal. Such an electric equipment system requires a large current when the steering wheel is rotated, or when the ABS unit is operated as a result of the use of heavy braking. In addition, an electric equipment system, which is driven in accordance with the operation of the driver and which consumes a large current, is provided in the cockpit, including, for example, the electric window and the air conditioning fan.
An AC-DC converter having a large capacity is required to simultaneously drive the electric equipment systems by using the alternating current supplied from the commercial AC power source. In this context, some of the electric equipment systems, which require large electric current consumption as described above, are not always driven, however, they are driven simultaneously in some cases.
However, if an AC-DC converter having a large capacity is introduced only for such a purpose, the cost of the drive simulation apparatus is increased. Further, an inconvenience arises, which results in the increase in weight and the increase in size.
It is clear for the drive simulation apparatus that the reality is further improved if a real image is displayed on the screen. For example, a situation is assumed in which the simulation is performed for an emergency vehicle. The running condition of neighboring other vehicles is different between a case in which the emergency vehicle runs in a state in which the siren is sounded, and a case in which the emergency vehicle runs in a state in which the siren is not sounded. Further, the drive simulation apparatus should be designed such that when the driver sounds a horn, a leading vehicle avoids the subjective vehicle.
However, the conventional apparatus is constructed such that although the image is changed depending on, for example, the steering operation, the braking operation, and the accelerator operation of the driver, the image is not changed by any operation other than the above.
In the case of a real vehicle, the swinging center is located at the center of gravity of the vehicle. On the contrary, in the case of the drive simulation apparatus, the swinging center is set on the side of the motion base in some cases. If the simulation is performed in such a state, the head of the driver is greatly separated from the swinging center. Therefore, especially when an action, which accompanies large acceleration or deceleration, is continued, the difference from the real vehicle is increased. Further, the driver occasionally suffers from so-called simulator motion sickness.
In a conventional technique disclosed in Japanese Laid-Open Patent Publication No. 8-248872, the control is made such that the point of swinging center approaches the head of the driver, as the acceleration or the deceleration of the cockpit is increased. By doing so, the discomfort feeling of the driver is mitigated.
However, when the action of the cockpit is controlled as described above, although the discomfort feeling is mitigated, it is feared that the driving feeling, which would be obtained in response to the action of a real vehicle, cannot be obtained in some situations.
Further, it is clear that such a drive simulation apparatus fails to achieve the sufficient leaning of skill and the sufficient research and development, if it is used in a form of use in which the driving technique is intended to be improved or the research and development are made by only the driver. In other words, for example, in order to improve the driving technique, it is indispensable to make appropriate monitoring and instruction by a skillful instructor. For the purpose of the research and development, it is clear that the work should be carried out by a plurality of researchers in cooperation with each other.
However, in the case of the conventional drive simulation apparatus, it is impossible for an external person to easily recognize, for example, the operation state of the various operation equipments operated by the driver. Therefore, a situation arises, in which the drive simulation apparatus cannot be utilized effectively.
Further, it is indispensable for the drive simulation apparatus to possess an emergency stop function. For example, if the control unit is erroneously operated due to any influence, it is impossible to deny the possibility that the swinging action of the motion base may be abnormal. For example, a situation may occur, in which the driver feels sick, and the driver himself desires the stop of simulation in some cases.
In order to respond to such situations, for example, it is easily conceived that the power source, which is used to supply the electric power to the entire drive simulation apparatus, is cut off by using a power source-interrupting device (breaker).
However, if the motion base is stopped by using the power source-interrupting device as described above, the control unit for constructing the drive simulation apparatus is also shut down. Therefore, for example, it is feared that the set data and the program may be destroyed.
The motion base makes it possible for the driver to physically feel the simulation state approximate to a real vehicle by the aid of the swinging action thereof. However, it is almost impossible for the driver to correctly recognize an actual operation state of the drive simulation apparatus as viewed from the outside. Therefore, for example, assuming a case in which the operation in the cockpit is abnormal, it is necessary to provide a system in which the operator always monitors the operation state from the outside. Further, there is a possibility that the motion base is out of order. If no countermeasure is made for such a situation, it is impossible to use the drive simulation apparatus for a long period of time.
A general object of the present invention is to provide a drive simulation apparatus which makes it possible to perform simulation in a state approximate to a real vehicle.
A principal object of the present invention is to provide a drive simulation apparatus which makes it possible to avoid occurrence of any inconvenience such as disconnection, send and receive a large amount of information between a cockpit for accommodating a driver and an external host computer, and perform simulation in a state approximate to a real vehicle.
Another object of the present invention is to provide a drive simulation apparatus which can be constructed to have a compact size and which makes it possible to realize a sufficient simulation action within a necessary and minimum movable range.
Still another object of the present invention is to provide a drive simulation apparatus which can be effectively utilized and which makes it possible to sufficiently contribute, for example, to the improvement in driving technique and the quick advance of research and development.
Still another object of the present invention is to provide a drive simulation apparatus which has a compact size, which is inexpensive, and which can be driven with sufficient electric power.
Still another object of the present invention is to provide a drive simulation apparatus which makes it possible to obtain a steering feeling equivalent to that obtained by a real vehicle.
Still another object of the present invention is to provide a drive simulation apparatus which makes it possible to perform simulation by using appropriate condition setting in response to operation of a driver.
Still another object of the present invention is to provide a drive simulation apparatus which makes it possible to perform simulation by arbitrarily selecting whether or not a motion base is operated.
Still another object of the present invention is to provide a drive simulation apparatus which sufficiently ensures a movable range and which makes it possible to apply a yawing action approximate to a real vehicle to a cockpit, without enlarging or complicating the apparatus.
Still another object of the present invention is to provide a drive simulation apparatus which makes it possible to realize a swinging action and a driving feeling approximate to those obtained by a real vehicle and which makes it possible to avoid any simulator motion sickness.
Still another object of the present invention is to provide a drive simulation apparatus which makes it possible to stop an action of a motion base easily and reliably without destroying, for example, data and programs.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.